To create "Public", we decided to make a functioning architectural model as well as a 3D flythrough. When we started this project it was always our desire to create a to-scale model that would move according to the data inputs we chose. To do this we would be using Arduino, sensors, Processing and servo motors.
Each of the four modules are moved by a servo motor which can move a mechanical arm 180degrees. This in turn pushes (and pulls) a piston capable of moving the modules up and down on the vertical Y axis. The servos are powered by and respond to an Arduino Uno board, which is also collecting data from the 3 sensors.
The Mind - Module 1 - Twitter (and hashtags)
We wanted Public to use twitter in two ways, first, to read tweets containing one of 3 hashtags (#the1public, #the2public, #the3public) and count how many times each hashtag had been used in a given amount of time. This is essentially a voting system. As we wanted the mind to represent the collective consensus of the visitors, this works well and also allows for direct interaction. Secondly, we wanted the building to auto-tweet the current room in the Mind module on show. The picture below is a screenshot of the Public twitter account having done this.
This was created using the twitter 4j library by Ben Quinney.
The Body - Module 2 - light sensor
Referring to light as a source of energy in plants and a provider of essential vitamins in humans, we chose to measure light as a representation of the body. There were 3 levels that the module could be in, and after reading the values from the sensor we decided that the ranges would be >0 + <20 = level 1, >21 + <80 = level 2, >81 = level 3. The code for this module is as follows:
lightVal = analogRead(lightSensor); //Light sensor module if(lightVal > 0 && lightVal <=20){ myservo2.write(0); Serial.println("Module 2, Level 1"); }else if (lightVal > 20 && lightVal <= 80){ myservo2.write(90); Serial.println("Module 2, Level 2"); }else{ myservo2.write(180); Serial.println("Module 2, Level 3"); }//END MODULE
The Soul - Module 3 - sound sensor
For the soul we chose a sound sensor as the noise produced by visitors to the gallery is an expression of their thoughts and opinions on the space, which we feel represents the soul. Here is the code for module 3:
soundVal = analogRead(soundSensor); //Sound sensor module if(soundVal > 0 && soundVal <=20){ myservo3.write(0); Serial.println("Module 3, Level 1"); }else if (soundVal > 20 && soundVal <= 80){ myservo3.write(90); Serial.println("Module 3, Level 2"); }else{ myservo3.write(180); Serial.println("Module 3, Level 3"); }//END MODULE
The Heart - Module 4 - ultrasound sensor embedded in the playscape
We're using an ultrasonic sensor to measure direct interaction with the playscape. This is the heart of the building as it's something the community can use and play with directly. And lo, the code for module 4:
pinMode(pingPin, OUTPUT); digitalWrite(pingPin, LOW); delayMicroseconds(2); digitalWrite(pingPin, HIGH); delayMicroseconds(5); digitalWrite(pingPin, LOW); pinMode(pingPin, INPUT); duration = pulseIn(pingPin, HIGH); cm = microsecondsToCentimeters(duration); if(cm > 0 && cm <=10){ myservo1.write(0); ultraSoundVis = 0; Serial.println("Module 4, Level 1"); }else if (cm > 10 && cm <= 20){ myservo1.write(90); ultraSoundVis = 90; Serial.println("Module 4, Level 2"); }else{ myservo1.write(180); ultraSoundVis = 180; Serial.println("Module 4, Level 3"); }//END MODULE
The playscape was designed by Chris Tough, and the physical model of it was created with card by myself. Here's a picture of the completed physical playscape model:
Days of construction in a cold garage
We spent 5 days in Jon Moore's garage constructing the physical model for Public. Though as Digital Art students I thought this might be difficult of us (seeing as we normally work in the digital and/or electronics worlds, not with saws, screws and MDF!) luckily we had engineer Jon Moore on our team and he created the brilliant step by step guide to building the model you can see HERE.
So we set about making Public. Below are a set of pictures depicting the step by step construction of the model:
Modules placed in location
Testing a single servo motor
Modules in place with model playscape
Testing all 4 motors with sensors attached
Here's a video showing the motors turning and responding to the data from the sensors
Encountering problems & resolving with visualisations
Despite testing the motors throughout construction of the model, once all 4 modules were in place the servos just weren't powerful enough to push the modules when on the model. We put this down to the amount of friction between the modules and the edge of the "floor" of the model. We didn't want the hole in the floor to be so big that the modules didn't stand upright, but it ended up being just a little too tight causing too much friction. This is such a shame as we'd all invested so much in to this project and the tech works great, we just made the simple mistake of not buying powerful enough motors.
(edit: After speaking to Mike Blow we are now looking in to getting more powerful motors as we really want to get this project working as we envisaged, even though the deadline has passed. Mike suggested the following:
I'd recommend using a normal motor and worm gear - that way the motor can run fast which it will prefer, and will give you a nice smooth motion. It also gears down to overcome the torque issues. You'll need an h-bridge circuit to alow you to run the motor backwards and forwards. Its all standard stuff - look on any of the robotics sites.
So to visualise which floor of the modules would be at ground level myself and Ben Quinney coded a visualisation in Processing. This proved difficult as although it was simple enough to send data from Processing to the arduino board, reading the values coming off the sensors on it was not easy. We used the Firmata libraries and managed to put this together:
amandla
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